The invention relates to a multipart cover made of paper material comprising a one-piece base body including a cover plate and a circumferential cover collar extending from the cover plate, wherein the cover collar, in a condition placed onto a container to be closed, extends upwards away from the container, and a reinforcement ring connected to the cover collar by means of a peripheral shroud or skirt. The invention also relates to a method for producing a multipart cover made of paper material.
The aim of the invention is to provide an improved multipart cover made of paper material and an improved method for producing a multipart cover made of paper material.
According to the invention a multipart cover made of paper material is provided, comprising a one-piece base body which includes a cover plate and a circumferential cover collar extending from the cover plate, wherein the cover collar, in a condition placed onto a container to be closed, extends upwards away from the container, and comprising a reinforcement ring connected to the cover collar by means of a peripheral skirt, wherein the reinforcement ring in a region below the cover plate, that is, on a side of the cover plate opposite to the cover collar, includes a peripheral skirt forming a circumferential step or shoulder along the periphery on a radially interior side of the reinforcement ring, or a circumferential bead along the periphery.
The invention provides a multipart cover made of paper material that, on the one hand, has a simple structure, and on the other hand, can be made in a stable configuration. A peripheral skirt forms a circumferential step along the periphery adapted to be used for hooked engagement of the cover on a lip rim or a lip roll of a container to be closed. Thereby the cover sits securely on a container to be closed. A skirt is meant to be a portion of the reinforcement ring which is folded over by 180° and pressed. Advantageously, the peripheral skirt is folded over by 180° below the cover plate and then comes to be placed on the material of the reinforcement ring. Thus, said skirt is merely to obtain a thickening of the reinforcement ring in its lower portion, however, there are not two components connected one to the other. In contrast thereto, the peripheral skirt of the reinforcement ring above the cover plate connects the reinforcement ring to the cover collar of the base body. For this, the reinforcement ring is equally folded over by 180° at the upper end thereof, however, the cover collar is then received between the two material layers of the folded over reinforcement ring. After pressing and adhesive bonding or sealing, as the case may be, the cover collar is fixedly connected to the reinforcement ring.
As an alternative to a peripheral skirt below the cover plate, a circumferential bead along the periphery is provided on the reinforcement ring. Even by means of the circumferential bead, a secure fitting of the cover according to the invention on a lip rim of a container to be closed may be obtained. The lip rim of the container may have, as seen here in cross section, a circular shape or even an oval shape, for example, when the lip rim is flattened. Incidentally, the expression “lip rim” may in general be used to designate an upper, reinforced rim of a container, for example a cup made of synthetic material including an upper, thickened rim.
In this context, paper as well as paper-type materials, e. g. paperboard, pasteboard, cardboard, or the like are considered to be paper materials, even paper material coated by wax or synthetic material on one side or on two sides. The coated surface of the paper material can be adapted to hot sealing.
In a further development of the invention, the bead extends radially outwards or inwards.
In this manner, a circumferential recess is created on the interior side of the reinforcement ring into which the lip rim of a container to be closed can then be received to snap-fit the cover on the container. The bead can be flattened, for example, and also an appropriately shaped locking element is referred to as a bead.
In a further development of the invention, the peripheral skirt above the cover plate is cylindrical.
The peripheral skirt above the cover plate is an essential element of the multipart cover according to the invention, since by means of the peripheral skirt above the cover plate the cover collar of the base body is fixedly connected to the reinforcement ring. The configuration of said skirt in a cylindrical shape facilitates the production thereof, since the skirt is readily accessible for a pressing tool from both sides. This applies both to the circular skirts and skirts or covers of arbitrary basic shape, for example triangular or rectangular and advantageously with rounded corners.
In a further development of the invention, an inner diameter of the reinforcement ring at the lower rim is greater than an outer diameter of the peripheral skirt above the cover.
In this manner, the reinforcement ring and its lower rim can be placed on the skirt above the cover plate of another cover such that multiple covers may be securely stacked onto another.
In a further development of the invention, the reinforcement ring is enlarged or flaring radially outwards in the region of the lower rim thereof.
Due to the enlargement, there is necessarily a step formed above the enlargement which may then be used as an abutment during stacking of multiple covers, to prevent that multiple stacked covers slide too far onto another and get jammed. The enlargement is configured in the shape of an outwards extending step, for example, to then form an abutment surface for the uppermost rim of the peripheral skirt above the cover plate of the respective lower cover.
In a further development of the invention, the peripheral skirt above the cover plate is configured in the shape of a truncated cone and tapering in a direction away from the cover plate.
In this manner, the stacking of multiple covers is facilitated since the respective upper cover can easily be placed onto the frustoconical tapering peripheral skirt of the respective lower cover.
In a further development of the invention, the reinforcement ring is configured in the shape of a truncated cone in the region of the lower rim thereof, and is enlarged in a direction away from the cover plate, with an inner diameter of the reinforcement ring at the lower rim thereof being greater than an outer diameter of the peripheral skirt at the upper edge.
In this manner, the frustoconical enlarged lower region of the reinforcement ring can be placed accurately fitting onto the frustoconical tapering skirt above the cover plate of the respective lower cover in a simple way such that secure stacking is feasible.
In a further development of the invention, the reinforcement ring below the cover plate is provided with a radially outwards extending, circumferential bead, with an inner diameter of the reinforcement ring at the lower rim thereof being greater than an outer diameter of the reinforcement ring immediately above the bead, and smaller than a greatest outer diameter in the region of the bead.
In this manner, the bead is, on the one hand, an abutment for stacking multiple covers, and on the other hand, an interior side of the outwards extending bead can snap-in on the lip rim of the container during placing onto a container to be closed, and thus ensure secure fitting of the cover on the container.
The problem underlying the invention is also solved by a method for producing a multipart cover made of paper material, comprising the following steps:
shaping a base body from a one-piece paper material cut-out, wherein the base body includes a cover plate and a circumferential cover collar extending from the cover plate,
shaping a reinforcement ring including a peripheral skirt which forms a circumferential step along the periphery on a radially interior side of the reinforcement ring, and/or,
shaping a reinforcement ring having a circumferential bead, and
connecting the reinforcement ring to the base body.
The succession of the method steps can be varied, and the bead can as well be shaped after connecting the reinforcement ring to the base body, for example.